1. Field of the Invention
This invention relates to electrostatic coating methods and apparatus.
2. Description of the Related Art
Insurance carriers increasingly require factories in which electrostatically aided coating operations are being conducted to comply with National Fire Protection Association (NFPA) regulations governing finishing processes. NFPA regulations distinguish between agency (usually Factory Mutual-FM) approved, or listed (resin or filled resin construction and resistive electrostatic power supply circuit), coating material dispensers, on the one hand, and unapproved (metal construction and often "stiff" electrostatic power supply circuit) coating material dispensers on the other. Bell-type applicators which utilize resinous materials in their construction and resistive electrostatic power supply circuits are known. See, for example, U.S. Pat. No. 4,887,770. Devices of the general type described in U.S. Pat. No. 4,887,770 achieve whatever safety they achieve at the sacrifice of transfer efficiency and flexibility in the types of coating materials that they can dispense.